E. S. Smith

Laboratory search for a long-range T-odd, P-odd interaction from axionlike particles using dual-species nuclear magnetic resonance with polarized 129Xe and 131Xe gas.

Various theories beyond the standard model predict new particles with masses in the sub-eV range with very weak couplings to ordinary matter. A new P-odd and T-odd interaction between polarized and unpolarized nucleons proportional to K·r is one such possibility, where r is the distance between the nucleons and K is the spin of the polarized nucleon. Such an interaction involving a scalar coupling gs at one vertex and a pseudoscalar coupling gp at the polarized nucleon vertex can be induced by the exchange of spin-0 bosons. We used the NMR cell test station at Northrop Grumman Corporation to search for NMR frequency shifts in polarized 129Xe and 131Xe when a nonmagnetic zirconia rod is moved near the NMR cell. Long (T2∼20  s) spin-relaxation times allow precision measurements of the NMR frequency ratios, which are insensitive to magnetic field fluctuations. Combined with existing theoretical calculations of the neutron spin contribution to the nuclear angular momentum in xenon nuclei, the measurements improve the laboratory upper bound on the product gsgp(n) by 2 orders of magnitude for distances near 1 mm. The sensitivity of this technique can be increased by at least two more orders of magnitude.

Laboratory search for spin-dependent short-range force from axionlike particles using optically polarized 3He gas

The possible existence of short-range forces between unpolarized and polarized spin-1/2 particles has attracted the attention of physicists for decades. These forces are predicted in various theories and provide a possible new source for parity (P) and time reversal (T) symmetry violation. We use an ensemble of polarized 3He gas in a cell with a 250 um thickness glass window to search for a force from scalar boson exchange over a sub-millimeter ranges. This interaction would produce a NMR frequency shift as an unpolarized mass is moved near and far from the polarized ensemble. We report a new upper bound on the product g_{s}g_{p}^{n} of the scalar couplings to the fermions in the unpolarized mass, and the pseudoscalar coupling of the polarized neutron in the 3He nucleus for force ranges from 1e-4 to 1e-2 m, which corresponds to a mass range of 2e-3 to 2e-5 eV for the scalar boson.

A Frequency Determination Method for Digitized NMR Signals

We present a high precision frequency determination method for digitized NMR FID signals. The method employs high precision numerical integration rather than simple summation as in many other techniques. With no independent knowledge of the other parameters of a NMR FID signal (phase

Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

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An initial study of mesons and baryons containing strange quarks with GlueX

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A study of meson and baryon decays to strange final states with GlueX in Hall D (A proposal to the 39th Jefferson Lab Program Advisory Committee)

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Evidence for the onset of color transparency in ρ0 electroproduction off nuclei

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Comment on 'Observation of a narrow structure in 1H(γ,K0S)X via interference with ϕ-meson production'

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Construction and Performance of the Barrel Electromagnetic Calorimeter for the GlueX Experiment

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A Metastability-Exchange Optical Pumping and Compression System using Polarized

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